tg3: Fix phylib locking strategy

Felix Radensky noted that chip resets were generating stack trace dumps.
This is because the driver is attempting to acquire the mdio bus mutex
while holding the tp->lock spinlock.  The fix is to change the code such
that every phy access takes the tp->lock spinlock instead.
Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/tg3.c

@@ -902,11 +902,12 @@ static int tg3_mdio_read(struct mii_bus *bp, int mii_id, int reg)
 	struct tg3 *tp = bp->priv;
 	u32 val;
 
-	if (tp->tg3_flags3 & TG3_FLG3_MDIOBUS_PAUSED)
-		return -EAGAIN;
+	spin_lock_bh(&tp->lock);
 
 	if (tg3_readphy(tp, reg, &val))
-		return -EIO;
+		val = -EIO;
+
+	spin_unlock_bh(&tp->lock);
 
 	return val;
 }
@@ -914,14 +915,16 @@ static int tg3_mdio_read(struct mii_bus *bp, int mii_id, int reg)
 static int tg3_mdio_write(struct mii_bus *bp, int mii_id, int reg, u16 val)
 {
 	struct tg3 *tp = bp->priv;
+	u32 ret = 0;
 
-	if (tp->tg3_flags3 & TG3_FLG3_MDIOBUS_PAUSED)
-		return -EAGAIN;
+	spin_lock_bh(&tp->lock);
 
 	if (tg3_writephy(tp, reg, val))
-		return -EIO;
+		ret = -EIO;
 
-	return 0;
+	spin_unlock_bh(&tp->lock);
+
+	return ret;
 }
 
 static int tg3_mdio_reset(struct mii_bus *bp)
@@ -1011,12 +1014,6 @@ static void tg3_mdio_config_5785(struct tg3 *tp)
 
 static void tg3_mdio_start(struct tg3 *tp)
 {
-	if (tp->tg3_flags3 & TG3_FLG3_MDIOBUS_INITED) {
-		mutex_lock(&tp->mdio_bus->mdio_lock);
-		tp->tg3_flags3 &= ~TG3_FLG3_MDIOBUS_PAUSED;
-		mutex_unlock(&tp->mdio_bus->mdio_lock);
-	}
-
 	tp->mi_mode &= ~MAC_MI_MODE_AUTO_POLL;
 	tw32_f(MAC_MI_MODE, tp->mi_mode);
 	udelay(80);
@@ -1041,15 +1038,6 @@ static void tg3_mdio_start(struct tg3 *tp)
 		tg3_mdio_config_5785(tp);
 }
 
-static void tg3_mdio_stop(struct tg3 *tp)
-{
-	if (tp->tg3_flags3 & TG3_FLG3_MDIOBUS_INITED) {
-		mutex_lock(&tp->mdio_bus->mdio_lock);
-		tp->tg3_flags3 |= TG3_FLG3_MDIOBUS_PAUSED;
-		mutex_unlock(&tp->mdio_bus->mdio_lock);
-	}
-}
-
 static int tg3_mdio_init(struct tg3 *tp)
 {
 	int i;
@@ -1141,7 +1129,6 @@ static void tg3_mdio_fini(struct tg3 *tp)
 		tp->tg3_flags3 &= ~TG3_FLG3_MDIOBUS_INITED;
 		mdiobus_unregister(tp->mdio_bus);
 		mdiobus_free(tp->mdio_bus);
-		tp->tg3_flags3 &= ~TG3_FLG3_MDIOBUS_PAUSED;
 	}
 }
 
@@ -1363,7 +1350,7 @@ static void tg3_adjust_link(struct net_device *dev)
 	struct tg3 *tp = netdev_priv(dev);
 	struct phy_device *phydev = tp->mdio_bus->phy_map[PHY_ADDR];
 
-	spin_lock(&tp->lock);
+	spin_lock_bh(&tp->lock);
 
 	mac_mode = tp->mac_mode & ~(MAC_MODE_PORT_MODE_MASK |
 				    MAC_MODE_HALF_DUPLEX);
@@ -1431,7 +1418,7 @@ static void tg3_adjust_link(struct net_device *dev)
 	tp->link_config.active_speed = phydev->speed;
 	tp->link_config.active_duplex = phydev->duplex;
 
-	spin_unlock(&tp->lock);
+	spin_unlock_bh(&tp->lock);
 
 	if (linkmesg)
 		tg3_link_report(tp);
@@ -6392,8 +6379,6 @@ static int tg3_chip_reset(struct tg3 *tp)
 
 	tg3_nvram_lock(tp);
 
-	tg3_mdio_stop(tp);
-
 	tg3_ape_lock(tp, TG3_APE_LOCK_GRC);
 
 	/* No matching tg3_nvram_unlock() after this because
@@ -8698,6 +8683,8 @@ static int tg3_close(struct net_device *dev)
 
 	del_timer_sync(&tp->timer);
 
+	tg3_phy_stop(tp);
+
 	tg3_full_lock(tp, 1);
 #if 0
 	tg3_dump_state(tp);

drivers/net/tg3.h

@@ -2748,7 +2748,6 @@ struct tg3 {
 #define TG3_FLG3_5701_DMA_BUG		0x00000008
 #define TG3_FLG3_USE_PHYLIB		0x00000010
 #define TG3_FLG3_MDIOBUS_INITED		0x00000020
-#define TG3_FLG3_MDIOBUS_PAUSED		0x00000040
 #define TG3_FLG3_PHY_CONNECTED		0x00000080
 #define TG3_FLG3_RGMII_STD_IBND_DISABLE	0x00000100
 #define TG3_FLG3_RGMII_EXT_IBND_RX_EN	0x00000200